1. Field of the Invention
The present invention relates generally to computers and communications equipment, and more particularly to a device and methods for interactive distribution of multimedia conference content over a computer network.
2. Description of the Prior Art
Videoconferencing systems have become an increasingly popular and valuable business communications tool. These systems facilitate rich and natural communication between persons or groups of persons located remotely from each other, and reduce the need for expensive and time-consuming business travel.
Videoconferences are often enriched through the sharing of slide presentations, to display text and graphics simultaneously with the personal interaction among the conference participants. A typical method for sharing slide presentation content among conference participants involves aiming of the videoconferencing camera at a screen onto which the presentation slides are being projected at a conference site, thereby transmitting the content to the other conference sites. This method is not ideal because directing the camera at the presentation may preclude simultaneously directing the camera at the participants, thus sacrificing the visual contact with the participants.
Traditional videoconferences are generally limited in the number of sites that may actively participate in the conference. The limitation stems from the limitations inherent to the videoconferencing equipment, which restrict the number of endpoint participants, and from the traditional data transmission networks utilized, such as the PSTN (public switched telephone network), a circuit switched network in which the communication path between the parties is dedicated to that communication and thus generally an inefficient utilization of resources. Videotaping the conference for mass distribution is one solution to the limited reach of conferences, but this is not ideal due to the passive nature of viewing a past event and the delay between the occurrence of the conference and the ability of non-participants to view the conference.
With the evolution of the Internet, data compression and data transmission technologies are being developed to facilitate the exchange of information among many users networked throughout the world. Some technologies allow a user to play and view multimedia content from their desktop computer, or other machine, running a standard player application.
What is needed in the videoconferencing art is a merger of high quality videoconferencing technology with efficient, state-of-the-art data compression and transmission technology, whereby the personal interaction occurring among the participants during a conference, and the associated slide presentations being viewed at the conference, can be distributed to a large audience in real time. An additional need exists for the ability of remote viewers to communicate with the conference participants during the conference.
An embodiment of the invention comprises a distribution device for distributing, or webcasting, audio/video content while simultaneously distributing synchronous presentation content (typically consisting of slides and documents) to remote terminals over a computer network via streaming technology. The multimedia content may originate from a live videoconference, and is transmitted to the distribution device through connections with a videoconference device.
The distribution device is preferably provided with a network interface for connecting the device to the computer network, audio/video and presentation data interfaces for receiving conference content, a file conversion engine for converting presentation content into a standard image format for distribution, and a stream encoder for encoding the content into streaming format for distribution. The distribution device is further equipped with a stream server for transmitting the encoded audio/video content and a web server for transmitting web pages and converted presentation content to terminals located at nodes of the network. The distribution device may additionally generate an archive file consisting of the encoded stream data, residing at local storage media, to enable later on-demand distribution to requestors at remote terminals over the computer network.
According to a typical mode of operation, a viewer at a remote terminal accesses a conference by directing a conventional web browser to an URL (Uniform Resource Locator) associated with the distribution device. After completion of validation data interchanges between the viewer and the distribution device, the viewer is able to view the personal interchange, i.e. the conversation and associated behavior, occurring between the participants at the conference presenter site, as well as view the presentation content being presented at the conference site. In one embodiment, the multimedia content is viewed in a multiple-window user interface through the viewer web browser, with the audio/video content presented by a streaming media player, and the presentation content displayed in a separate window. Additionally, the user interface includes an interactive text entry interface, which provides to the viewer the capability to transmit comments or questions to the conference participants at the conference site. The participants can review and reply to the comments or questions in real time.
In another embodiment, the distribution device can be configured to allow certain viewers at the remote terminals to contribute presentation content to the conference. A presenter toolbar having presentation controls is displayed at the remote terminal, and the user may effect predetermined presentation-related operations (e.g., selecting a presentation file or advancing slides within a selected file) by engaging the appropriate controls on the toolbar. This viewer-contributed presentation content is uploaded to the distribution device, through which it is encoded and streamed to remote viewers along with the audio/video content stream originating from the conference site.
In yet another embodiment, the distribution device is coupled to a separate remote streaming server, to provide the capability to distribute content at higher bandwidths and to more viewers than is available with the stream server internal to the device. In addition, the distribution device may be coupled to a separate network server, to provide higher bandwidth distribution to more viewers than is available with the stream server internal to the device, and to provide the capability to host plural conference streams generated by a corresponding plurality of distribution devices. According to this architecture, the distribution device repetitively transmits the current and the successive presentation data image files to the network server for caching, whereby the network server can notify a viewer through the viewer web browser that presentation content is available. Upon encountering a streamed presentation event, the viewer web browser can immediately receive and locally cache the presentation content from the network server prior to arrival of the associated audio/video content, thus minimizing latency in the display of the presentation content in coordination with the audio/video content.